LANSING, MI - Republican Gov. Rick Snyder on Tuesday did what was once unthinkable in a state with strong ties to organized labor - signed a law that will make Michigan the 24th state to prohibit requiring workers to pay union dues or fees as a condition of employment.

At about 5:45 p.m., Snyder announced publicly that he signed the historic right-to-work legislation in private - hours after the bills won final approval in the House and five days after he joined with GOP legislative leaders to announce their plan to enact the controversial law.

"This is a major day in Michigan's history," he said during a news conference in the Romney building not long after signing the legislation. "Again, I don't view this as anti-union at all. I believe this is pro-worker."

He gave two main reasons for supporting the law - giving workers choice and keeping Michigan's economy competitive, citing Indiana's decision to become a right-to-work state earlier this year. He also said a union-led ballot drive that went down to defeat in November - and which he warned labor leaders not to pursue - "triggered" discussions about the issue.

"It was time to step up and take a leadership position, which I believe I've done," Snyder said.

Opponents of right-to-work laws say assertions of their economic benefits lack proof and say employees who do not pay dues or fees should not be able to "freeload" by getting compensation and contract protections paid for with the dues of union members.

Critics also say the real motivation is to weak unions both financially and therefore politically, while Snyder says unions will just have to work harder to convince members it is worth contributing to their cause.

The first-term governor signed the bill on a day that an estimated 12,500 demonstrators showed up in Lansing to protest the bills, both inside and outside the Capitol and outside of the nearby Romney building where the governor's offices are located.

The right-to-work law became a reality with lightning speed, first winning approval Thursday in the Legislature with no committee hearings or prior glimpse at the bills.

At noon Tuesday, the state House gave final approval to the first of two right-to-work bills. They voted on the second bill hours later.

After the House approved one bill, protesters who were crowded outside the House chamber immediately began chanting "Veto! Veto! Veto!"

Dozens began a peaceful sit-in protest on the first floor of the Capitol rotunda. "Sit down, fight back!" they yelled to loud applause from crowds looking down from higher floors. They received a visit from Jesse Jackson, Senate Minority Leader Gretchen Whitmer and other Democrats.

"I'm disgusted. And I hope he's not such a coward that he signs them the way that they are," Whitmer told reporters hours before Snyder did in fact sign the bills. "I hope he vetoes them. At the very least, I hope he takes out the appropriation so that people will have the right of referendum."

Asked why not let people have a chance to repeal the law through a referendum, Snyder said he viewed the right-to-work bills as being "part of the normal legislative process."

He said nothing will stop citizens from trying a 2014 ballot drive on the right-to-work issue.